During the past several years the Department of Defense (DOD) and the Department of Energy (DOE) have made a significant effort to find a replacement for currently used lead styphanate-based percussion primers due to their toxicity. Several metastable nanoenergetic composites (MNC, also known as metastable interstitial composites or superthermites), including Al—MoO3, Al—WO3, Al—CuO and Al—Bi2O3, were identified as the potential substitutes for currently used lead styphanate. These materials have shown excellent performance characteristics, such as impact sensitivity, high temperature output and low temperature ignition limit. However, it has been found that the MNC systems, despite of their excellent performance characteristics, are difficult to process safely. The main difficulty is handling of dry MNC powder mixtures due to their sensitivity to friction and electrostatic discharge (ESD).
It has been demonstrated at a laboratory scale that it is possible to mix nanosize (i.e., granules with dimensions on the order of <10−6 m) aluminum and oxidizer powders in low-boiling temperature solvents using ultrasonic devices. After the mixing, the solvent is vaporized and MNC mixture is collected from the drying pan. The MNC powder is weighed and dry-loaded into percussion primer cups. Unfortunately, this process has several drawbacks which prevent its scale-up. These drawbacks include: i) the necessity of using organic solvents, ii) potentially inadequate dispersion and mixing, iii) drying and handling of sensitive MNC mixtures, iv) dry-loading of sensitive MNC mixtures, and v) adverse susceptibility of the MNC percussion primers to humid air and liquid water. Up to now, there has been no reported research work addressing the use of surface modifiers and additives to efficiently prevent reaction of aluminum nanopowders with water, to improve dispersion and mixing in liquid water and to reduce the ESD, friction and impact sensitivities during processing and loading of percussion primers. All these outlined processing characteristics are essential for scale-up of percussion primer production.